Lucas is Lilly's ex-boyfriend who appeared in the episode My Best Friend's Boyfriend and was portrayed by Sterling Knight.
In My Best Friend's Boyfriend, he's said to be Lilly's first real boyfriend, and at first, Miley's happy for Lilly, but then Miley starts getting annoyed with their relationship and feeling like a third wheel when Lilly keeps blowing her off to hang out with Lucas. But then Miley sees Lucas making out with another girl, showing that he was cheating on Lilly. Of course, Miley tells Lilly about it, but Lilly doesn't believe her, thinking that Miley's just jealous. Although later, Lilly (as Lola) finds out that Lucas really is cheating on her. She apologizes to Miley for not believing her, and they promise that they should always trust each other no matter what.